Associations among tooth loss, denture use, and dementia in older Taiwanese adults

Background: The literature has mainly focused on the association between tooth loss and dementia, and evidence regarding the separate and joint effects of tooth loss and denture use on the risk of dementia is limited. This study investigated the links among tooth loss, denture use, and dementia risk in Taiwanese adults aged 65 years or older. Methods: This retrospective cohort study utilized data from the 2009 National Health Interview Survey and 2008-2017 National Health Insurance claim records, including the records of 2247 individuals free from dementia treatment in 2008-2009. Dementia diagnoses were tracked until 2017. The Cox proportional hazards model was used to calculate hazard ratios (HRs) for exploring the correlations among tooth loss, denture use, and dementia risk. Results: Although older adults who had 20 or more natural teeth and used dentures had the lowest dementia incidence (1.43 per 100 person-years) among participants, those with fewer than 20 natural teeth, with or without dentures, experienced high dementia incidence rates of 2.31 and 3.33 per 100 person-years, respectively. After adjusting for sociodemographic characteristics, health conditions/comorbidities, and lifestyles, having fewer than 20 natural teeth (vs. ≥20 remaining natural teeth) or not using dentures (vs. ≥20 remaining natural teeth) was found to be associated with increased but not statistically significant HRs of 1.299 (95% confidence interval [CI], 0.986-1.710) and 1.199 (95% CI, 0.945-1.521). Subgroup analysis revealed that compared with older adults with 20 or more natural teeth and dentures, those with fewer than 20 natural teeth and not wearing dentures had a significantly increased risk of dementia (adjusted HR, 1.569; 95% CI, 1.038-2.370). Conclusion: This study found that having fewer than 20 natural teeth and not using dentures was significantly associated with an increased risk of dementia in Taiwanese individuals aged 65 years or above.